Ask Dr. Dairy: Does the source of calcium matter?

Yes, the source of calcium matters – and while people may know that adequate calcium contributes to bone health, many Americans are not getting enough.

Nutrition experts agree it’s best to get your nutrients, including calcium, from foods. That’s because whole foods like calcium-rich milk, cheese and yogurt contain several vitamins, minerals and other components associated with promoting health. But when medical or practical reasons make it difficult to get enough calcium from foods that are naturally rich in calcium, calcium-fortified foods or calcium supplements can help fill the gap.

Dairy foods, such as milk, yogurt and cheese, are the main food source of calcium for most people in the U.S. In fact, on average, milk is the top food source of calcium, vitamin D and potassium for Americans age 2 and older. USDA determined serving sizes for milk, yogurt and cheese based on calcium content. One cup of milk or yogurt and 1 ½ ounces of natural cheese each contain about 300 mg of calcium. Milk contains nine essential nutrients, including calcium, important for bone health.

Other food sources of calcium include vegetables such as kale, broccoli and Chinese cabbage; bony fish like canned sardines and salmon (when the soft bones are eaten); and calcium-fortified foods such as breakfast cereals, fruit juices and soy beverage.

Vegetables generally contain quite a bit less calcium per serving than milk, so if you’re relying on vegetables to meet your calcium needs, you’ll need to eat a lot of them. For example, you would need to eat about 38 cups of raw kale to get the amount of calcium in three glasses of milk, as this infographic illustrates.

Plant-based alternative beverages made from soy, almond, rice, hemp and others are sometimes fortified with calcium, but in varying amounts. Reading labels is important to understand the nutrients provided in these products.

Research has shown that replacing dairy foods with other food sources of calcium within a healthy eating pattern would require a significant change in the eating habits of most Americans. In fact, you’d need 1.1 servings of fortified soy beverage or 1.2 servings of bony fish, or 2.2 servings of leafy greens, to equal the calcium in one serving of milk.

While dairy foods provide 54% of the calcium in the diets of Americans over the age of two years, milk substitutes, fish and shellfish, dark green vegetables and lettuce all provide less than 3% of the calcium in the diet. A diet modelling study verified that if everyone ate the recommended servings of dairy foods, Americans, on average, would get adequate calcium.

If you’re not getting enough calcium from the food you eat, a dietitian or health care provider may recommend a dietary supplement. According to a Calcium Fact Sheet from the Office of Dietary Supplements, the amount of calcium in supplements varies. Check the Supplement Facts label and talk to your doctor about your calcium needs and intake.